docs: def args(
          self, all_solutions=False, num_solutions=None, free_search=False,
          parallel=None, seed=None, **kwargs
      ):
          """Returns a list of command line arguments for the specified options.
  
          If the solver parser is able to parse statistics, this function should
          always add options to display statistics.
  
          Parameters
          ----------
          all_solutions : bool
              Whether all the solutions must be returned (default is False).
          num_solutions : int
              The maximum number of solutions to be returned (only used in
              satisfation problems).
          free_search : bool
              Whether the solver should be instructed to perform a free search.
          parallel : int
              The number of parallel threads the solver should use.
          seed : int
              The random number generator seed to pass to the solver.
          """
          args = ['-s', '-v']
          if all_solutions:
              args.append('-a')
          if num_solutions is not None:
              args += ['-n', num_solutions]
          if free_search:
              args.append('-f')
          if parallel is not None:
              args += ['-p', parallel]
          if seed is not None:
              args += ['-r', seed]
          return args